People in the past were often afflicted with intestinal parasites, and researchers from the University of Copenhagen and Aarhus University have scouring ancient latrines for parasite eggs for genetic analysis to better understand ancient diets and health, NPR reports.
The researchers collected parasite eggs from latrine sites in Europe and the Middle East. By sequencing the DNA they uncovered, they found a number of soil-borne parasites, but also ones transmitted through meat and fish, as they report in PLOS One this week. This, they add, provides a glimpse into what ancient people were eating. For instance, they report that the presence of Diphyllobothrium latum and Taenia solium — helminths transmitted by eating undercooked fish and pork, respectively.
"[W]e see that [Northern Europeans] ate a lot of fish because they were eating fish tapeworms," first author Martin Søe from Copenhagen tells NPR.
At the same time, they found DNA traces from domesticated animals as well as wild ones. For instance, they found DNA from fin whales in a Danish sample, which suggests that people were either hunting or collecting whale meat.
He and his colleagues also uncovered DNA belonging to parasites that infect sheep, dogs, pigs, and others, suggesting they lived in close contact with people.